Liquid Feed Tube for Liquid Jetting Device and Liquid Jetting Device

ABSTRACT

A liquid feed tube for feeding a liquid from a liquid tank disposed on a liquid jetting device body side to a jetting head mounted on a reciprocating carriage, including: a long elastic member and a film member connected in an airtight state to the elastic member along a longitudinal direction of the elastic member; and a space part formed by the elastic member and the film member and used as a liquid feed passage, wherein the elastic member is made of a specific resin composition. Thus, the bending rigidity of the liquid feed tube can be lowered, and the resistance to moisture permeability and the gas barrier property thereof can be realized at low cost.

TECHNICAL FIELD

The present invention relates to a liquid feed tube for feeding a liquidfrom a liquid tank disposed on a liquid jetting device body side to ajetting head mounted on a reciprocating carriage, and a liquid jettingdevice using the same.

BACKGROUND ART

Up to now, as a liquid jetting device for jetting a liquid to a target,there is an ink-jet recording apparatus that jets an ink droplet topaper to print an image or the like thereon. This ink-jet recordingapparatus includes a jetting head (hereinafter, referred to as recordinghead), which is mounted on a carriage and reciprocates in a mainscanning direction, and means for transporting a target (hereinafter,referred to as recording sheet) in a sub-scanning directionperpendicular to the main scanning direction, and jets a liquid droplet(hereinafter, referred to as ink droplet) from a recording head based onjetting data (hereinafter, referred to as printing data), wherebyprinting is performed with respect to the recording sheet. In most ofthe recording apparatus of this type mainly used for home use, eachliquid tank (referred to as ink tank) for feeding ink to a recordinghead is configured so as to be attached/detached with respect to acarriage on which the recording head is mounted.

In a recording apparatus of an on-carriage type in which an ink tank ismounted on a carriage as described above, it is difficult to use an inktank with a large capacity, and hence, in the case where an attempt ismade to execute printing of a relatively large amount, it is necessaryto replace an ink tank frequently. This not only requires the work for areplacement operation of a tank, but also increases a running cost.

Thus, for example, in the recording apparatus of this type used for acommercial purpose, a configuration of an off-carriage type is adoptedin which an ink tank with a large capacity is placed on a body side of arecording apparatus, and ink is fed respectively to a recording headmounted on a carriage via a flexible liquid feed tube (hereinafter,referred to as ink feed tube) from the ink tank (for example, see PatentDocument 1). Further, regarding a low-hardness thermoplastic materialfor an ink-jet printer, there is description in Patent Document 2.

Patent Document 1: JP 2003-320680 A

Patent Document 2: WO 03/027183

DISCLOSURE OF THE INVENTION

In such a recording apparatus of the off-carriage type, as a print size(i.e., size of a printable sheet) increases, an ink feed tube run lengthbecomes larger, so the dynamic pressure (i.e., pressure loss) in the inkfeed tube from an ink tank to a carriage becomes large. This makes itnecessary to adopt ink feed tubes each having a larger inner diameter.

In addition, in most of the ink feed tubes used in the above-mentionedrecording apparatus of the off-carriage type, the cross-section thereofis set to be a circular shape, and hence, the bending rigidity thereofis basically large. Thus, in case of adopting ink tubes having largerinner diameter as mentioned above, the bending rigidity furtherincreases. Therefore, in order to overcome the bending rigidity, it isnecessary to further enhance the driving force of the carriage. Further,each tube must be designed so that the bending diameter thereof becomeslarger along with the increase in the bending rigidity. In any case, therecording apparatus is caused to be further enlarged.

On the other hand, in the above-mentioned ink feed tube, it is necessaryto suppress the evaporation of moisture that forms a main part of an inkmedium, and further, there is a problem in that the outside air isdissolved in the ink in the tube to decrease a deaeration degree of theink. Therefore, it may adopt to enlarge the thickness of an ink feedtube. However, in the case of enlarging the thickness of the tube inthis manner, the above-mentioned increase in the bending rigidity of thetube becomes conspicuous.

As a material for forming a tube, it may adopt to use a low-hardnessthermoplastic material with high airtightness as described in PatentDocument 2. However, in order to obtain a material with a low hardnessso as to decrease the rigidity of the tube, it is necessary to add alarge amount of liquid polymer and oil component, and consequently, theairtightness of the material may be degraded.

Further, a suggested method is to form a tube in two layers or threelayers so as to enhance the resistance to moisture permeability and thegas barrier property. However, forming a tube configured so as to have across-section of a circular shape in a multi-layered structure basicallycannot avoid involving the above-mentioned increase in bending rigidity.Further, forming the tube into two-layer or three-layer structure, a dieor the like for forming each layer is required for an extruder, whichcauses an increase in costs.

The present invention has been made in view of the above-mentionedtechnical problem of a liquid feed tube for feeding a liquid from aliquid tank disposed on a liquid jetting device body side to a jettinghead on a carriage side as in the above-mentioned ink-jet recordingapparatus, and an object of the present invention is to provide a liquidfeed tube for a liquid jetting device capable of realizing theresistance to moisture permeability and the gas barrier property withlow cost, as well as decreasing the bending rigidity thereof, and aliquid jetting device.

A liquid feed tube according to the present invention which has beenmade to attain the above-mentioned object is a liquid feed tube forfeeding a liquid from a liquid tank disposed on a liquid jetting devicebody side to a jetting head mounted on a reciprocating carriage,comprising: a long elastic member and a film member connected in anairtight state to the elastic member along a longitudinal direction ofthe elastic member; and a space part formed by the elastic member andthe film member and used as a liquid feed passage, wherein the elasticmember is made of a resin composition containing (A) a (b)-(a)-(b) typeisobutylene-based triblock copolymer having (a) a polymer block mainlyincluding an isobutylene unit and (b) a polymer block mainly including astyrene unit, (B) an ethylene-based polymer and/or a propylene-basedpolymer, and (C) a liquid polybutene, and having the following features(first invention):

(1) an air permeability [JIS K7126; A-method (differential pressuremethod), 40° C.] measured using a sheet sample with a thickness of 0.5mm is 200 cm³/(m²·24 hr·atm) or less;

(2) a moisture permeability (JIS Z0208; 40° C., 90% RH) measured using asheet sample with a thickness of 0.5 mm is 2.0 g/(m²·24 hr) or less;

(3) a hardness [JIS K6253 (15 seconds later) is 30 to 60 degrees interms of JIS-A hardness; and

(4) a melt flow rate [MFR] (JIS K7210; 190° C., 52.185 N(5.325 Kgf)) is100 g/10 minutes or less.

Alternatively, the liquid feed tube of the present invention ischaracterized in that the elastic member is composed of a resincomposition containing (D) a (b)-(a)-(b) type isobutylene-based triblockcopolymer with a weight-average molecular weight of 50,000 to 80,000,having (a) a polymer block mainly including an isobutylene unit and (b)a polymer block mainly including a styrene unit and (E) a (d)-(c)-(d)type isobutylene-based triblock copolymer with a weight-averagemolecular weight of 90,000 to 130,000, having (c) a polymer block mainlyincluding an isobutylene unit and (d) a polymer block mainly including astyrene unit in a mass ratio of 20:80 to 60:40, and having the followingfeatures (second invention):

(1) an air permeability [JIS K7126; A-method (differential pressuremethod), 40° C.] measured using a sheet sample with a thickness of 0.5mm is 200 cm³/(m²·24 hr·atm) or less;

(2) a moisture permeability (JIS Z0208; 40° C., 90% RH) measured using asheet sample with a thickness of 0.5 mm is 2.0 g/(m²·24 hr) or less;

(3) a hardness [JIS K6253 (15 seconds later) is 30 to 60 degrees interms of JIS-A hardness; and

(4) a melt flow rate [MFR] (JIS K7210; 270° C., 98.066 N(10 Kgf)) is5000 g/10 minutes or less.

According to a liquid jetting device using a liquid feed tube of thepresent invention, the liquid feed tube includes: a long elastic memberand a film member connected to the elastic member in an airtight statein a longitudinal direction of the elastic member; and a space partformed by the elastic member and the film member and used as a liquidfeed passage, in which a particular member is used as the elasticmember. Therefore, the bending rigidity thereof can be decreased, andthe degree at which resistance is given to the reciprocating movement ofa carriage can be reduced remarkably.

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1] A perspective view showing an entire configuration of arecording apparatus using an ink feed tube according to the presentinvention.

[FIG. 2] A perspective view showing an external appearance configurationof the ink feed tube used in the recording apparatus shown in FIG. 1.

[FIG. 3] A front view showing an enlarged state of the ink feed tubeshown in FIG. 2, seen from a connecting member side attached to an endportion of the ink feed tube.

[FIG. 4] A cross-sectional view showing a state taken along the line A-Aof FIG. 3 in a direction of arrows.

[FIG. 5] A cross-sectional view showing a state taken along the line B-Bof FIG. 4 in a direction of arrows.

[FIG. 6] A cross-sectional view showing a C portion surrounded by achain line of FIG. 5 in an enlarged state.

[FIG. 7] A perspective view showing an end portion of the ink feed tubein a perspective state.

[FIG. 8] A perspective view showing an example in which a damperfunction is provided to a part of the ink feed tube.

[FIG. 9] A cross-sectional view and a perspective view showing anotherpreferable example of the ink feed tube.

[FIG. 10] A cross-sectional view and a perspective view showing stillanother preferable example of the ink feed tube.

DESCRIPTION OF SYMBOLS

1 carriage

5 sheet feed member as means for transporting target

7 recording sheet as target

8 recording head as jetting head

10 capping means

13 wiping member

15 tank holder

16B to 16Y ink tank as liquid tank

17, 19 connected member

20 ink feed tube as liquid feed tube

20 a bent portion

21 connecting member

22 connecting tube formed in a cylindrical shape

23 connecting tube formed in a prism shape

25 opening portion

31 elastic member

32 film member

33 ink feed passage (space part) as liquid feed passage

34 thin film (aluminum laminate layer)

36 cut-away portion

37 enlarged space part

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an ink-jet recording apparatus using an ink feed tubeaccording to the present invention will be described with reference toan embodiment shown in the drawings. FIG. 1 is a perspective viewshowing a basic configuration of a recording apparatus body. In FIG. 1,reference numeral 1 denotes a carriage, and the carriage 1 is configuredso as to be guided by a guide member 4 to reciprocate in a main scanningdirection along a longitudinal direction of a sheet feed member 5 via atiming belt 3 driven by a carriage motor 2.

A sheet feed roller 6 is placed on the sheet feed member 5, and arecording sheet 7 sandwiched by the sheet feed roller 6 and a drivenroller (not shown) is transported in a sub-scanning directionperpendicular to the above-mentioned main scanning direction by therotation of the sheet feed roller 6. In this case, a number ofprotrusions 5 a are formed intermittently along a longitudinal directionon an upper surface of the sheet feed member 5, and the recording sheet7 is transported along the upper surface of the protrusions 5 a.

Then, on a lower side surface of the carriage 1 opposed to the recordingsheet 7, an ink-jet recording head 8 as represented by a broken line ismounted, and an ink droplet is jetted appropriately by the recordinghead 8 based on printing data, whereby printing can be performed on therecording sheet 7.

On the other hand, reference numeral 10 denotes capping means placed ina non-printing region (i.e., home position), and the capping means 10can move upward to seal a nozzle formation surface (lower side surfaceof the recording head 8 in the present embodiment) of the recordinghead, when the recording head 8 moves immediately above the cappingmeans 10. A suction pump 11 forgiving a negative pressure to an internalspace part of the capping means 10 is placed below the capping means 10.

The capping means 10 functions as a lid for sealing the nozzle formationsurface of the recording head 8 to suppress the evaporation of an inkmedium from a nozzle opening during a non-operating period of therecording apparatus, and allows the negative pressure from the suctionpump 11 to the recording head 8 and ink is caused to be sucked anddischarged from the recording head, whereby the capping means 10 canexecute a cleaning operation of maintaining the ink jetting function ofthe recording head.

As shown in FIG. 1, on a printing region side adjacent to the cappingmeans 10, a wiping member 13 in which elastic materials such as rubberare formed in a strip shape is placed, and when the carriage 1reciprocates to the capping means 10 side, the wiping member 13 proceedsor recedes in a horizontal direction to the movement path of therecording head, if required, thereby performing a wiping operation ofcleaning by wiping the nozzle formation surface of the recording head 8.

On the other hand, as shown in FIG. 1, in an end portion (right endportion of FIG. 1) of the recording apparatus, a tank holder 15 isprovided. In the tank holder 15, as ink tanks, a black ink tank 16B forfeeding black ink and respective color ink tanks 16C, 16M, and 16Y forfeeding cyan, magenta, and yellow inks can respectivelyattached/detached from the front side of the apparatus.

Ink transport tubes 18 are connected to a first connected member 17mounted on an upper portion of the tank holder 15 from the tank holder15 in which each ink tank is attached, and ink is fed from each of theabove-mentioned ink tanks to the first connected member 17 via each inktransport tube 18.

In the present embodiment, although not shown, an outer case of each ofthe above-mentioned ink tanks is configured in an airtight state, and aflexible ink pack with ink sealed therein is accommodated in each tankcase. Then, by supplying pressure air in the outer case constituting theink tank, each ink is pushed out by pressure air.

On the other hand, a second connected member 19 is also mounted on anupper portion of the above-mentioned carriage 1, and end portions of anink feed tube 20 according to the present invention are connected to thefirst and second connected members 17 and 19 via connecting membersdescribed later, respectively. Because of this, ink from each ink tankis fed to the carriage side individually, and an ink droplet is jettedby the above-mentioned recording head based on printing data.

In the embodiment shown in FIG. 1, the ink feed tube 20 formed in a flatand long shape is adopted. The ink feed tube 20 is extended in ahorizontal direction so that a band-shaped flat surface is in ahorizontal state from the above-mentioned first connecting member 17,bent in the horizontal direction via a U-shaped bent portion 20 a, andconnected to the above-mentioned second connected member 19. Thus, theU-shaped bent portion 20 a formed in the above-mentioned ink feed tube20 successively shifts in the longitudinal direction of the ink feedtube along with the movement of the carriage 1.

FIG. 2 shows an external appearance configuration of the ink feed tube20 adopted in the recording apparatus shown in FIG. 1. First and secondconnecting members 21 a and 21 b made of synthetic resin arerespectively attached to the respective end portions of the ink feedtube 20. In the present embodiment, ink from each of four ink tanks 16B,16C, 16M, and 16Y attached to the tank holder 15 is fed to the recordinghead side, and thus, four connecting tubes 22 a and 22 b formed incylindrical shapes are respectively formed on the respective connectingmembers 21 a and 21 b so as to correspond to the four ink tanks.

The respective connecting tubes 22 a formed on the first connectingmember 21 a are connected to the first connected member 17 shown in FIG.1, and the respective connecting tubes 22 b formed on the secondconnecting member 21 b are connected to the second connected member 19shown in FIG. 1, whereby each ink is fed to the recording head 8 mountedon the carriage 1. Reference numeral 20 a shown in FIG. 2 shows theabove-mentioned U-shaped bent portion formed during actual use of theink feed tube 20 in this embodiment.

FIGS. 3 to 6 show the configuration in an enlarged state of each part ofthe ink feed tube 20 whose external appearance configuration is shown inFIG. 2. In other words, FIG. 3 shows a state of the first or secondconnecting members 21 a or 21 b seen from an end portion side thereof,and FIG. 4 is a cross-sectional view taken along the line A-A of FIG. 3in a direction of arrows. Further, FIG. 5 is a cross-sectional viewtaken along the line B-B of FIG. 4 in a direction of arrows, and FIG. 6is a cross-sectional view showing a C portion surrounded by a chain linein FIG. 5 in an enlarged state. Note that, the above-mentioned first andsecond connecting members 21 a and 21 b are formed in the same shape,and hence, in FIGS. 3 to 6, both connecting members are denoted withreference numeral 21 typically, and all connecting tubes in acylindrical shape formed on each connecting member are denoted withreference numeral 22 typically.

As shown in FIG. 5, the ink feed tube 20 has a configuration in whichfive elastic members 31 are arranged in parallel at an equal interval.On one surface and another surface, i.e., upper and lower surfaces, ofeach of the elastic members 31, film members 32 formed similarly in along shape is connected to each of the elastic members 31 in an airtightstate by heat welding. Consequently, four space parts surrounded by theadjacent elastic members 31 and upper and lower film members 32 are setto be ink feed passages as denoted with reference numeral 33 of FIG. 6,and the respective ink feed passages 33 are formed independently along along flat surface via the respective elastic members 31.

The first invention of the present invention is characterized in thatthe elastic member 31 is made of a resin composition containing (A) a(b)-(a)-(b) type isobutylene-based triblock copolymer having (a) apolymer block mainly including an isobutylene unit and (b) a polymerblock mainly including a styrene unit, (B) an ethylene-based polymerand/or propylene-based polymer, and (C) liquid polybutene, and havingthe following features:

(1) an air permeability [JIS K7126; A-method (differential pressuremethod), 40° C.] measured using a sheet sample with a thickness of 0.5mm is 200 cm³/(m²·24 hr·atm) or less;

(2) a moisture permeability [(JISZ0208; 40° C., 90% RH) measured using asheet sample with a thickness of 0.5 mm is 2.0 g/(m²·24 hr) or less;

(3) a hardness [JIS K6253 (15 seconds later) is 30 to 60 degrees interms of JIS-A hardness; and

(4) a melt flow rate [MFR] (JIS K7210; 190° C., 52.185 N (5.325 Kgf)) is100 g/10 minutes or less.

Further, it is preferable that the elastic member 31 is a resincomposition having the following feature in which

(5) tensile strength and elongation (JISK6251; dumbbell-shape No. 3shape, 23° C.) are 5 MPa or more and 400% or more, respectively.

In the isobutylene-based triblock copolymer of the above-mentioned (A)component, (a) the polymer block mainly including an isobutylene unitdenotes a polymer block in which an isobutylene unit occupies 50 mass %or more, preferably 70 mass % or more, and more preferably 90 mass % ormore. The monomer forming units other than an isobutylene unit in thepolymer block mainly including an isobutylene unit is not particularlylimited as long as it is a cation-polymerizable monomer. Examplesthereof include monomers such as: aromatic vinyls; aliphatic olefins;dienes such as isoprene, butadiene, and diviylbenzene; allylethers; andβ-pinene They may be used alone or in combination of two or more kinds.

On the other hand, (b) the polymer block mainly including a styrene unitdenotes a polymer block in which a styrene unit occupies 50 mass % ormore, preferably 70 mass % or more, and more preferably 90 mass % ormore. The monomer forming units other than a styrene unit in the polymerblock mainly including a styrene unit is not particularly limited aslong as it is a cation-polymerizable monomer. Examples thereof includemonomers such as: aromatic vinyls such as α-methylstyrene,β-methylstyrene, p-methylstyrene, tert-butylstyrene, monochlorostyrene,dichlorostyrene, methoxystyrene, and indene; aliphaticolefins; dienes;allylethers; and β-pinene. They may be used alone or in combination oftwo or more kinds.

The isobutylene-based triblock copolymer of the above-mentioned (A)component used for compounding is a (b)-(a)-(b) type, and there is noparticular limit to the content ratio between (a) the polymer blockmainly including an isobutylene unit and (b) the polymer block mainlyincluding a styrene unit. However, in terms of the physical propertiesof a resin composition to be obtained, the content ratio is preferably(a) the polymer block mainly including an isobutylene unit of 60 to 85mass % and (b) the polymer block mainly including a styrene unit is 40to 15 mass %, and more preferably (a) the above-mentioned polymer blockof 65 to 80 mass % and (b) the above-mentioned polymer block of 35 to 20mass %.

Further, there is no particular limit to the weight-average molecularweight of the isobutylene-based triblock copolymer of theabove-mentioned (A) component used for compounding. However, in terms ofthe mechanical characteristics and moldability of a resin composition tobe obtained, a range of 40,000 to 200,000 is preferable, and inparticular, a range of 50,000 to 150,000 is more preferable. Theweight-average molecular weight is a value under polystyrene conversionmeasured by gel permeation chromatography (GPC method).

There is no particular limit to a method of producing theisobutylene-based triblock copolymer, and a conventionally known methodcan be used. For example, by using an inifer method (for example, amethod disclosed by the specification of U.S. Pat. No. 4,276,394) ofperforming living cationic polymerization using a monofunctionalcomponent such as α-chlor-isopropylbenzene, a bifunctional componentsuch as 1,4-bis(α-chloroisopropyl)benzene (also called p-dicumylchloride), or a trifunctional component such as1,3,5-tris(α-chloroisopropyl)benzene as an initiator and chain transferagent, and using Lewis acid such as BCl₃ or TiCl₄ as a catalyst, apolymer mainly including an isobutylene unit of a controlled molecularweight is formed, and subsequently, a monomer mainly including styreneis added to cause copolymerization, whereby a desired isobutylene-basedtriblock copolymer can be obtained.

In the resin composition of the first invention, as the (B) component,an ethylene-based polymer and/or a propylene-based polymer are/is used.

Examples of the ethylene-based polymer include high-density,medium-density, and low-density polyethylenes, linear low-densitypolyethylene, ultra high molecular weight polyethylene, anethylene-vinyl acetate copolymer, and an ethylene-ethyl acrylatecopolymer.

On the other hand, examples of the propylene-based polymer include apropylene single polymer, a propylene-ethylene block copolymer, a randomcopolymer, and a propylene-ethylene-diene compound copolymer. Amongthem, crystalline polypropylene-based resin is preferable, and examplesof the crystalline polypropylene-based resin include an isotacticpropylene single polymer having crystallinity, an ethylene-propylenerandom copolymer containing a small amount of ethylene units, apropylene block copolymer composed of a homo part made of a propylenesingle polymer and a copolymer part made of an ethylene-propylene randomcopolymer containing a relatively large amount of ethylene units, and acrystalline propylene-ethylene-α-olefin copolymer obtained bycopolymerizing each homo part or copolymer part in the propylene blockcopolymer with a-olefin such as butene-1.

By containing the (B) component, the heat seal property of a resincomposition is enhanced, and the shrinkage ratio thereof during moldingdecreases.

In the resin composition according to the first invention, as the (B)component, one kind or two or more kinds of the above-mentionedethylene-based polymer may be mused, and one kind or two or more kindsof the propylene-based polymer may be used. Further, at least one kindof the ethylene-based polymer may be combined with at least one kind ofthe propylene-based polymer.

In the resin composition according to the first invention, as the liquidpolybutene used as the (C) component, the one having a number-averagemolecular weight of about 200 to 3,000 mainly including an isobutyleneunit is preferable. As such liquid polybutene, for example, a lowpolymer mainly including isobutylene obtained by copolymerizing a slightamount of butene-1 produced using, as it is, the remaining fraction thatis obtained by extracting butadiene from a C₄ fraction generated bynaphtha cracking, or liquid butyl rubber obtained by copolymerizing asmall amount of isoprene with a low polymer of high-purity isobutyleneor isobutylene. They may be used alone in one kind, or in a combinationof two or more kinds. Owing to the presence of those liquid polybutenes,in the resin composition, the water vapor barrier properties as well asthe flexibility of the resin composition are enhanced.

The resin composition according to the first invention of the presentinvention has properties shown below.

First, the air permeability [JISK7126; A-method (differential pressuremethod), 40° C.] measured using a sheet sample with a thickness of 0.5mm based on an A-method (differential pressure method) of JIS K7126 is200 cm³/(m²·24 hr·atm) or less, which shows excellent gas barrierproperty. The air permeability is preferably 180 cm³/(m²·24 hr·atm) orless, and more preferably 160 cm³/(m²·24 hr·atm) or less. Although thereis no particular lower limit to the air permeability, it is usually 50cm³/(m²·24 hr·atm).

Further, the moisture permeability (JIS Z0208; 40° C., 90% RH) measuredusing a sheet sample with a thickness of 0.5 mm based on JIS Z0208 is2.0 g/(m²·24 hr) or less, which shows excellent barrier properties withrespect to water vapor. The moisture permeability is preferably 1.8g/(m²·24 hr) or less, more preferably 1.7 g/(m²·24 hr) or less, and mostpreferably 1.5 g/(m²·24 hr). Although there is no particular lower limitto the moisture permeability, it is usually 0.5 g/(m²·24 hr).

The hardness measured based on JIS K6253 (15 seconds later) is 30 to 60degrees in terms of JIS-A hardness. If the hardness is in the aboverange, the resin composition has satisfactory flexibility andappropriate mechanical physical properties.

Melt flow rate [MFR] (JIS K7210; 190° C., 52.185 N (5.325 Kgf)) is 10g/10 minutes or less. If the MFR is in the above range, the resincomposition has satisfactory injection moldability and satisfactorymechanical physical properties. The MFR is preferably 10 to 80 g/10minutes, and more preferably 10 to 60 g/10 minutes.

Further, based on JIS K6251, the tensile strength and elongation (JISK6251; dumbbell-shape No. 3 shape, 23° C.) are preferably 5 MPa or moreand 400% or more, respectively, and more preferably 6 MPa or more and500% or more, respectively.

In order for the resin composition of the present invention to have theabove-mentioned properties, the content ratio of the (A) component, (B)component, and (C) component in the resin composition according to thepresent invention are preferably 5 to 40 parts by mass of the (B)component and 5 to 40 parts by mass of the (C) component based on 100parts by mass of the (A) component, and more preferably 10 to 30 partsby mass of the (B) component and 15 to 35 parts by mass of the (C)component based on 100 parts by mass of the (A) component.

The second invention of the present invention is characterized in thatthe elastic member 31 is composed of a resin composition containing (D)a (b)-(a)-(b) type isobutylene-based triblock copolymer with aweight-average molecular weight of 50,000 to 80,000, having (a) apolymer block mainly including an isobutylene unit and (b) a polymerblock mainly including a styrene unit and (E) a (d)-(c)-(d) typeisobutylene-based triblock copolymer with a weight-average molecularweight of 90,000 to 130,000, having (c) a polymer block mainly includingan isobutylene unit and (d) a polymer block mainly including astyrene-unit, in a mass ratio of 20:80 to 60:40, and having thefollowing features:

(1) an air permeability [JIS K7126; A-method (differential pressuremethod), 40° C.] measured using a sheet sample with a thickness of 0.5mm is 200 cm³/(m²·24 hr·atm) or less;

(2) a moisture permeability (JISZ0208; 40° C., 90% RH) measured using asheet sample with a thickness of 0.5 mm is 2.0 g/(m²·24 hr) or less;

(3) a hardness [JIS K6253 (15 seconds later) is 30 to 60 degrees interms of JIS-A hardness; and

(4) a melt flow rate [MFR] (JISK7210; 270° C., 98.0665 N (10 Kgf)) is5000 g/10 minutes.

Further, it is preferable that the elastic member 31 is a resincomposition having the following feature in which

(5) tensile strength and elongation (JISK6251; dumbbell-shape No. 3shape, 23° C.) are 5 MPa or more and 300% or more, respectively.

In each of the isobutylene-based triblock copolymers of theabove-mentioned (D) component and (E) component, (a) the polymer blockmainly including an isobutylene unit and (c) the polymer block mainlyincluding an isobutylene unit each denote a polymer block in which anisobutylene unit occupies 50 mass % or more, preferably 70 mass % ormore, and more preferably 90 mass % or more. The monomer forming unitsother than an isobutylene unit in the polymer block mainly including anisobutylene unit is not particularly limited as long as it is acation-polymerizable monomer. Examples thereof include monomers such as:aromatic vinyls; aliphatic olefins; dienes such as isoprene, butadiene,and diviylbenzene; allylethers; and β-pinene. They may be used alone orin combination of two or more kinds.

On the other hand, (b) the polymer block mainly including a styrene unitand (d) the polymer block mainly including a styrene unit each denote apolymer block in which a styrene unit occupies 50 mass % or more,preferably 70 mass % or more, and more preferably 90 mass % or more. Themonomer forming units other than a styrene unit in the polymer blockmainly including a styrene unit is not particularly limited as long asit is a cation-polymerizable monomer. Examples thereof include monomerssuch as: aromatic vinyls such as α-methylstyrene, β-methylstyrene,p-methylstyrene, tert-butylstyrene, monochlorostyrene, dichlorostyrene,methoxystyrene, and indene; aliphaticolefins; dienes; allylethers; andβ-pinene. They may be used alone or in combination of two or more kinds.

The isobutylene-based triblock copolymer of the (D) component and theisobutylene-based triblock copolymer of the (E) component are a(b)-(a)-(b) type and a (d)-(c)-(d) type, respectively, and there is noparticular limit to the content ratio between (a) the polymer blockmainly including an isobutylene unit and (b) the polymer block mainlyincluding a styrene unit, and the content ratio between (c) the polymerblock mainly including an isobutylene unit and (d) the polymer blockmainly including a styrene unit. However, in terms of the physicalproperties of a resin composition to be obtained, the content ratio ispreferably the polymer block mainly including an isobutylene unit of 60to 85 mass % and the polymer block mainly including a styrene unit of 40to 15 mass %, and more preferably the polymer block mainly including anisobutylene unit of 65 to 80 mass % and the polymer block mainlyincluding a styrene unit of 35 to 20 mass %.

In the present invention, the content ratio of the polymer block mainlyincluding an isobutylene unit and the polymer block mainly including astyrene unit may be the same or different between the isobutylene-basedtriblock copolymer of the (D) component and the isobutylene-basedtriblock copolymer of the (E) component.

Further, in the present invention, the above-mentioned weight-averagemolecular weight of the isobutylene-based triblock copolymer of the (D)component is selected in a range of 50,000 to 80,000, and theweight-average molecular weight of the isobutylene triblock copolymer ofthe (E) component is selected in a range of 90,000 to 130,000. When theweight-average molecular weight of the (D) component is less than50,000, although a resin composition to be obtained has satisfactorymoldability, it has large compression permanent deformation and a poorrestoring property. On the other hand, when the weight-average molecularweight of the (E) component exceeds 130,000, a resin composition to beobtained has poor moldability, making it difficult to perform injectionmolding. Note that, the weight-average molecular weight is a value underpolystyrene conversion measured by gel permeation chromatography (GPCmethod).

In the present invention, the compounding ratio between theabove-mentioned isobutylene-based triblock copolymer of the (D)component, and the isobutylene-based triblock copolymer of the (E)component is selected in a mass ratio range of 20:80 to 60:40. If thecompounding ratio is in the above range, a resin composition havingpredetermined properties can be obtained, and the object of the presentinvention can be achieved. The preferable compounding ratio is in a massratio range of 25:75 to 45:55.

There is no particular limit to a method of producing theisobutylene-based triblock copolymer, and a conventionally known methodcan be used. For example, by using an inifer method (for example, amethod disclosed by the specification of U.S. Pat. No. 4,276,394) ofperforming living cationic polymerization using a monofunctionalcomponent such as α-chlor-isopropylbenzene, a bifunctional componentsuch as 1,4-bis(α-chloroisopropyl)benzene (also called p-dicumylchloride), or a trifunctional component such as1,3,5-tris(α-chloroisopropyl)benzene as an initiator and chain transferagent, and using Lewis acid such as BCl₃ or TiCl₄ as a catalyst, apolymer mainly including an isobutylene unit of a controlled molecularweight is formed, and subsequently, a monomer mainly including styreneis added to cause copolymerization, whereby a desired isobutylene-basedtriblock copolymer can be obtained.

The resin composition according to the second invention of the presentinvention has properties shown below.

First, the air permeability [JISK7126; A-method (differential pressuremethod), 40° C.] measured using a sheet sample with a thickness of 0.5mm based on an A-method (differential pressure method) of JIS K7126 is200 cm³/(m²·24 hr·atm) or less, which shows excellent gas barrierproperty. The air permeability is preferably 180 cm³/(m²·24 hr·atm) orless, and more preferably 160 cm³/(m²·24 hr·atm) or less. Although thereis no particular lower limit to the air permeability, it is usually 50cm³/(m²·24 hr·atm).

Further, the moisture permeability (JIS Z0208; 40° C., 90% RH) measuredusing a sheet sample with a thickness of 0.5 mm based on JIS Z0208 is2.0 g/(m²·24 hr) or less, which shows excellent barrier properties withrespect to water vapor. The moisture permeability is preferably 1.8g/(m²·24 hr) or less, more preferably 1.7 g/(m²·24 hr) or less, and mostpreferably 1.5 g/(m²·24 hr). Although there is no particular lower limitto the moisture permeability, it is usually 0.5 g/(m²·24 hr).

The hardness measured based on JIS K6253. (15 seconds later) is 30 to 60degrees in terms of JIS-A hardness. If the hardness is in the aboverange, the resin composition has satisfactory flexibility andappropriate mechanical physical properties.

Melt flow rate [MFR] (JISK7210; 270° C., 98.0665N (10 Kgf)) is 5,000g/10 minutes or less. If the MFR is in the above range, the resincomposition has satisfactory injection moldability and satisfactorymechanical physical properties. The MFR is preferably 3,000 g/10 minutesor less, and more preferably 1,000 g/10 minutes or less.

Further, the tensile strength and elongation (JIS K6251; dumbbell-shapeNo. 3 shape, 23° C.) are preferably 5 MPa or more and 300% or more,respectively, and more preferably 6 MPa or more and 500% or more,respectively.

In the resin composition according to the present invention, in additionto the above-mentioned (A) to (E) components, various additives, forexample, other thermoplastic elastomers and other olefin-based resins,and further, a plasticizer, a filling material, a reinforcing agent, asilane coupling agent, an adhesion providing agent, a radialcrosslinking agent, a crosslinking aid, an anti-aging agent (aphenol-based antioxidant, an aromatic amine-based antioxidant, asulfur-based hydroperoxide decomposer, a phosphorus-based hydroperoxidedecomposer, a benzotriazole-based ultraviolet absorber, asalicylate-based ultraviolet absorber, a benzophenone-based ultravioletabsorber, a hindered amine-based light stabilizer, a nickel-based lightstabilizer, etc.), a photocurable resin, waxes, a flowable modifier, alubricant, a surfactant, a foaming agent, a flame retardant, a pigment,and the like can be appropriately compounded, if desired, in a rangethat does not impair the object of the present invention.

As a melt kneading apparatus, for example, a sealed kneading apparatusor a batch-type kneading apparatus such as a labo plastmill, aBrabender, a Banbury mixer, a kneader, or a roll, or a continuous meltkneading apparatus such as a uniaxial extruder or a biaxial extruder canbe used.

The resin composition of the present invention thus obtained can bemolded by a molding method and a molding apparatus generally adoptedwith respect to a thermoplastic resin composition, and can bemelt-molded by, for example, extrusion molding, injection molding, pressmolding, blow molding, or the like.

These resin compositions can be easily heat-welded with synthetic resinconstituting the film member 32, and a satisfactory airtight state canbe ensured by performing heat welding. Further, the resin composition isa flexible material, and as shown in FIGS. 1 and 2, it can be bent in aU shape easily on its flat surface, whereby the degree at whichresistance is given to the reciprocating movement of a carriage can bedecreased.

Further, each surface of each film member 32 constituting the ink feedtube 20 is previously provided with a thin film 34 by aluminum laminateprocessing as shown in FIG. 6. Because of this, the ink feed tube 20 canbe provided with the gas barrier property and the resistance to moisturepermeability effectively.

On the other hand, on the connecting member 21 attached to each endportion of the above-mentioned ink feed tube 20, as shown in FIGS. 3 and4, a connecting tube 23 formed in a prism shape is formed at a positionopposed to each connecting tube 22 formed in a cylindrical shape. Then,an opening portion 25 is formed so as to pass through the cylindricalconnecting tube 22 and the prismatic connecting tube 23. Theabove-mentioned prismatic connecting tube 23 is connected to each inkfeed passage 33 formed in the ink feed tube 20 in each end portion ofthe ink feed tube 20.

In other words, the above-mentioned film members 32 are heat-welded toupper and lower surfaces of the above-mentioned prismatic connectingtube 23, as shown in FIG. 6, and further, the prismatic connecting tube23 is press-fitted in an elastic member 31 on the right and left sides.It is desirable that side walls on the right and left sides of theprismatic connecting tube 23 to be press-fitted in the elastic member 31are previously coated with an adhesive so that an airtight state withrespect to the elastic member 31 after press-fitting can be held.Alternatively, it is preferable that a connecting member is formed usingresin having compatibility with a resin composition of the elasticmember, and the elastic member and the connecting member are integrallyformed by insert processing or the like.

FIG. 7 shows a perspective state in which the connecting member 21 isattached to the end portion of the above-mentioned ink feed tube 20, andshows the components corresponding to the respective portions alreadydescribed with the same reference numerals.

In an off-carriage type recording apparatus of this type, the pressurefluctuation of ink may be caused on a recording head side due to theacceleration received by ink in the ink feed tube along with thereciprocating movement of the carriage 1. Thus, in the recordingapparatus of this type, a damper member is mounted on a carriage,whereby the above-mentioned pressure fluctuation of ink is absorbed.

However, in the ink feed tube 20 described above, the ink feed passage33 surrounded by the elastic members 31 and the film members 32 isallowed to have a damper function particularly by the elasticity of thefilm members 32. Thus, a recording apparatus that is not particularlyrequired to have a damper member can also be provided using the ink feedtube 20 with the above-mentioned configuration.

On the other hand, in the ink feed tube 20 with the above-mentionedconfiguration, the damper function may not be obtained sufficiently bythe film members 32. Then, as shown in FIG. 8, the followingconfiguration, in which: cut-away portions 36 are provided in opposedparts of the respective adjacent elastic members 31, whereby enlargedspace parts 37 with intervals of the opposed elastic member 31 extendedare formed, can be preferably used. FIG. 8 shows a state in which thefilm member 32 on the upper surface is removed.

According to this configuration, owing to the enlarged space parts 37, aportion having a large area with the film members 32 can be ensured in apart of the ink feed tube 20, whereby the damper function can beexhibited effectively. It is desirable that the above-mentioned enlargedspace parts 37 are disposed on the downstream side of the ink feedpassage 33 in the ink feed tube 20, i.e., on the carriage 1 side.

Next, FIG. 9 shows another preferable example of the ink feed tubeaccording to the present invention. FIG. 9A is a cross-sectional viewtaken along the line D-D in a direction of arrows of FIG. 9B. FIG. 9B isa perspective view showing a state in which the longitudinal directionof the ink feed tube is shortened. In the ink feed tube 20 shown in FIG.9, the pair of long elastic members 31 are arranged in parallel to eachother, and on one surface and another surface of each elastic member 31,the film members 32 are connected in an airtight state. Then, a spacepart surrounded by each elastic member 31 and film member 32 constitutesan ink feed passage 33.

Even in the ink feed tube 20 shown in FIG. 9, it is desirable that anelastomer is used as the elastic member 31, and the upper and lower filmmembers 32 are heat-welded to the elastomer, whereby the elastic member31 and the film members 32 are connected in an airtight state. Further,although not shown in FIG. 9, it is desirable that a thin film 34 ispreviously provided on each outside portion of the upper and lower filmmembers 32 by aluminum laminate processing in the same way as in theexample shown in FIG. 6.

Also in the ink feed tube 20 shown in FIG. 9, connecting members made ofsynthetic resin are attached to both end portions, and the ink feed tube20 is connected between the first and second connecting members 17 and19 shown in FIG. 1, whereby ink is fed from the ink tank to therecording head side. Further, in the embodiment shown in FIG. 9, one inkfeed passage 33 is formed for one ink feed tube 20. Therefore, in therecording apparatus with the configuration shown in FIG. 1, four inkfeed tubes 20 are used independently.

Also in the embodiment of the ink feed tube 20 shown in FIG. 9, arelatively soft material is selected as an elastomer that serves as theelastic member 31, whereby the degree at which resistance is given tothe reciprocating movement of the carriage can be reduced remarkably. Athin film is provided on each surface of the film members 32constituting the ink feed tube 20 by aluminum laminate processing asdescribed, whereby the ink feed tube 20 can be provided with the gasbarrier property and the resistance to moisture permeabilityeffectively.

Finally, FIG. 10 shows still another preferable example of the ink feedtube according to the present invention. FIG. 10A is a cross-sectionalview taken along the line E-E in a direction of arrows of FIG. 10B. FIG.10B is a perspective view showing a state in which the longitudinaldirection of the ink feed tube is shortened. In the ink feed tube 20shown in FIG. 10, on one surface and another surface of the long elasticmember 31, both ends of the film member 32 perpendicular to thelongitudinal direction thereof is connected in an airtight state.

In other words, the film member 32 is connected to two surfaces of theelastic member 31 in a bag shape, whereby the ink feed passage 33 isformed. Because of this, the peripheral length by the film member 32 isformed larger than the peripheral length by the elastic member 31 on theinner surface of the ink feed passage 33, i.e., the thickness of theelastic member 31.

Even in the ink feed tube 20 shown in FIG. 10, an elastomer is used asthe elastic member 31, and the film member 32 is heat-welded to theelastomer serving as the elastic member 31 in a bag shape, whereby theelastic member 31 and the film member 32 are connected in an airtightstate. Further, although not shown in FIG. 10, it is desirable that thethin film 34 is previously provided on the outside portion of the filmmember 32 to be connected in a bag shape by aluminum laminate processingin the same way as in the example shown in FIG. 6.

Also in the ink feed tube 20 shown in FIG. 10, connecting members madeof synthetic resin are attached to both end portions, and the ink feedtube 20 is connected between the first and second connecting members 17and 19 shown in FIG. 1, whereby ink is fed from the ink tank to therecording head side. Further, in the embodiment shown in FIG. 10, oneink feed passage 33 is formed for one ink feed tube 20. Therefore, inthe recording apparatus with the configuration shown in FIG. 1, four inkfeed tubes 20 are used independently.

As well as the previous embodiments, in the embodiment of the ink feedtube 20 shown in FIG. 10, a relatively soft material is selected as anelastomer that functions as the elastic member 31, whereby the degree atwhich resistance is given to the reciprocating movement of the carriagecan be reduced remarkably. A thin film is provided on a surface of thefilm member 32 constituting the ink feed tube 20 by aluminum laminateprocessing as described, whereby the ink feed tube 20 can be providedwith the gas barrier property and the resistance to moisturepermeability effectively.

In each of the above embodiments, as the liquid jetting device, arecording apparatus (i.e., a printing apparatus including a facsimile ora copier) discharging ink has been described. However, other liquidjetting devices for jetting a liquid may be used. For example, a liquidjetting device for jetting a liquid of an electrode material, a coloringmaterial, or the like used in the production of a liquid crystaldisplay, an EL display, and a surface-emitting display, a liquid jettingdevice for jetting a bio-organic material used in the production of abiochip, and a sample jetting device serving as a precision pipette maybe used.

INDUSTRIAL APPLICABILITY

In the liquid jetting device using a liquid feed tube according to thepresent invention, the liquid feed tube includes: a long elastic member;a film member connected in an airtight state to the elastic member alongthe longitudinal direction of the elastic member; and a space partformed by the elastic member and the film member and used as a liquidfeed passage, and a particular member is used as the elastic member.Therefore, the bending rigidity thereof can be decreased, and the degreeat which resistance is given to the reciprocating movement of thecarriage can be reduced remarkably. Further, a thin film such as analuminum laminate layer is formed previously on the above-mentioned filmmember constituting the liquid feed tube, whereby the resistance tomoisture permeability and the gas barrier property of the liquid feedtube can be realized at low cost.

1. A liquid feed tube for feeding a liquid from a liquid tank disposedon a liquid jetting device body side to a jetting head mounted on areciprocating carriage, comprising: a long elastic member and a filmmember connected in an airtight state to the elastic member along alongitudinal direction of the elastic member; and a space part formed bythe elastic member and the film member and used as a liquid feedpassage, wherein the elastic member is made of a resin compositioncontaining (A) a (b)-(a)-(b) type isobutylene-based triblock copolymerhaving (a) a polymer block mainly including an isobutylene unit and (b)a polymer block mainly including a styrene unit, (B) an ethylene-basedpolymer and/or a propylene-based polymer, and (C) a liquid polybutene,and having the following features: (1) an air permeability [JIS K7126;A-method (differential pressure method), 40° C.] measured using a sheetsample with a thickness of 0.5 mm is 200 cm³/(m²·24 hr·atm) or less; (2)a moisture permeability (JIS Z0208; 40° C., 90% RH) measured using asheet sample with a thickness of 0.5 mm is 2.0 g/(m²·24 hr) or less; (3)a hardness [JIS K6253 (15 seconds later) is 30 to 60 degrees in terms ofJIS-A hardness; and (4) a melt flow rate [MFR](JIS K7210; 190° C.,52.185 N (5.325 Kgf)) is 100 g/10 minutes or less.
 2. The liquid feedtube according to claim 1, wherein the resin composition further has thefollowing feature: (5) tensile strength and elongation (JIS K6251;dumbbell-shape No. 3 shape, 23° C.) are 5 MPa or more and 400% or more,respectively.
 3. A liquid feed tube for feeding a liquid from a liquidtank disposed on a liquid jetting device body side to a jetting headmounted on a reciprocating carriage, comprising: a long elastic memberand a film member connected in an airtight state to the elastic memberalong a longitudinal direction of the elastic member; and a space partformed by the elastic member and the film member and used as a liquidfeed passage, wherein the elastic member is made of a resin compositioncontaining (D) a (b)-(a)-(b) type isobutylene-based triblock copolymerwith a weight-average molecular weight of 50,000 to 80,000, having (a) apolymer block mainly including an isobutylene unit and (b) a polymerblock mainly including a styrene unit and (E) a (d)-(c)-(d) typeisobutylene-based triblock copolymer with a weight-average molecularweight of 90,000 to 130,000, having (c) a polymer block mainly includingan isobutylene unit and (d) a polymer block mainly including a styreneunit, in a mass ratio of 20:80 to 60:40, and having the followingfeatures: (1) an air permeability [JIS K7126; A-method (differentialpressure method), 40° C] measured using a sheet sample with a thicknessof 0.5 mm is 200 cm³/(m²·24 hr·atm) or less; (2) a moisture permeability(JIS Z0208; 40° C., 90% RH) measured using a sheet sample with athickness of 0.5 mm is 2.0 g/(m²·24 hr) or less; (3) a hardness [JISK6253 (15 seconds later) is 30 to 60 degrees in terms of JIS-A hardness;and (4) a melt flow rate [MFR](JIS K7210; 270° C., 98.0665 N (10 Kgf))is 5000 g/10 minutes or less.
 4. The liquid feed tube according to claim3, wherein the resin composition further has the following feature: (5)tensile strength and elongation (JIS K6251; dumbbell-shape No. 3 shape,23° C.) are 5 MPa or more and 400% or more, respectively.
 5. A liquidjetting device, characterized by comprising the liquid feed tubeaccording to claim
 1. 6. A liquid jetting device, characterized bycomprising the liquid feed tube according to claim 3.